Rod Suspension System for Integrated Wellhead

ABSTRACT

An artificial lift system for a well having a wellhead reciprocates a rod string with an uphole pump unit at the wellhead to operate a downhole pump unit in the well and lift fluid in the well. A rod segment coupled to the rod string at the wellhead has first opposing surfaces facing in first opposing directions. Opposing catchers are movable laterally relative to the rod segment at the wellhead. Each of the catchers has a face with second opposing surfaces facing in second opposing directions opposite to the first opposing directions. The catchers moved in a first condition have the second opposing surfaces disengaged from the first opposing surfaces of the rod segment, but the catchers moved in a second condition have the second opposing surfaces engaged with the segment&#39;s first opposing surfaces to hold the rod string in place.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Prov. Appl. No. 62/106,569,filed 22 Jan. 2015, which is incorporated herein by reference.

BACKGROUND OF THE DISCLOSURE

Many hydrocarbon wells are unable to produce at commercially viablelevels without assistance in lifting the formation fluids to the earth'ssurface. In some instances, high fluid viscosity inhibits fluid flow tothe surface. More commonly, formation pressure is inadequate to drivefluids upward in the wellbore. In the case of deeper wells,extraordinary hydrostatic head acts downwardly against the formation andinhibits the unassisted flow of production fluid to the surface.

A common approach for urging production fluids to the surface uses amechanically actuated, positive displacement pump. Reciprocal movementof a string of sucker rods induces reciprocal movement of the pump forlifting production fluid to the surface. For example, a reciprocatingrod lift system S of the prior art is shown in FIG. 1 to produceproduction fluid from a wellbore B. As is typical, surface casing Changs from the surface and has a liner casing L hung therefrom by aliner hanger H. Production fluid from the formation F outside cement CTcan enter the liner L through perforations P. To convey the fluid,production tubing T extends from a wellhead W downhole, and a packer PKseals the annulus between the production tubing T and the liner L. Atthe surface, the wellhead W receives production fluid from the tubing Tand diverts it to a flow line FL.

The production fluid may not produce naturally reach the surface sooperators use the reciprocating rod lift system S to lift the fluid. Thesystem S has a surface pumping unit SPU, a rod string RS, and a downholepump unit DPU. Any number of surface pumping units SPU can be used, suchas a pump jack shown, hydraulic unit, or the like. The surface pumpingunit SPU reciprocates the rod string RS, and the reciprocating string RSoperates the downhole pump unit DPU to lift produced fluid up theproduction tubing T to the wellhead W. Any number of downhole pump unitsDPU can be used, such as the rod pump shown having the barrel andplunger.

Whenever service is required on the reciprocating rod lift system S,some means of suspending the rod string RS at the wellhead W is requiredto facilitate any service operations that are required. Conventionalwellheads W have seal rams to seal around the polished rod sections ofthe rod string RS, but there generally is not a way to suspend the rodstring RS. This problem has been addressed by the so-called rod lockwellhead system described in U.S. Pat. No. 6,223,819 to Double-E Inc.

For example, FIG. 2 shows the prior art lock assembly 23 disclosed inU.S. Pat. No. 6,223,819. The lock assembly 23 is used on a wellhead 10,which has upper and lower bodies 11 and 12 secured together by nut-boltassemblies 13. A bore 15 extends through the bodies 11, 12 for a suckerrod or string 20 to extend through the wellhead to a downhole pump (notshown).

The lock assembly 23 is mounted in the upper body 11 for supporting therod string 20 and to prevent the rod string 20 from being accidentallyreleased. The assembly 23 includes a support rod 24, an operator screw25, and a support sleeve or nut 30. Shown in a locked or engagedposition in FIG. 2, the assembly 23 locks the rod string 20 out ofoperation and supports the rod string 20 from the wellhead.

As shown in FIGS. 3A-3B, the support rod 24 is a cylindrical member witha keyway 31 formed in the first or outward end of the rod for couplingthe operator screw 25 with the rod 24. The inward end of the support rod24 has an open ended vertical 2-step slot 32. A lower slot portion 32 ais sized to fit around the rod string 20 below a coupling flange 33 onthe rod string 20, and an upper larger slot portion 32 b serves as alocking slot sized to receive the coupling flange 33 on the rod string20 for supporting the rod string 20.

The upper slot portion 32 b is formed with inward vertical curvedsurface portions 32 c and with vertical locking flanges 32 d, which arespaced apart laterally to accommodate the diameter of the rod string 20below the rod string locking flange 33. The larger size of the upperslot portion 32 b relative to the lower slot portion 32 a provides asupport shoulder surface 32 e.

The support rod 24 can be moved laterally to an engaged position onlywhen the rod string 20 is lifted to an elevation at which the couplingflange 33 is above the support rod upper slot portion 32 b. When thesupport rod 24 is moved inwardly by the operator screw 25 to the engagedposition, the rod string 20 may be lowered with the flange 33 on the rodstring 20 moving downwardly entering the upper slot portion 32 b to reston the shoulder surface 32 e. At this position, the curved slot surfaces32 c fit inwardly or wrap somewhat around the rod flange 33 so that thevertical lock flanges 32 d prevent the support rod 24 from being movedlaterally out of engagement with the rod string 20. The support rod 24can be disengaged from the rod string 20 when the rod string 20 islifted upwardly to a position at which the coupling flange 33 is not inthe upper slot portion 32 b of the support rod 24.

As illustrated in FIG. 2, the operator screw 25 fits through and isthreadingly engaged with a sleeve 30 so that rotation of the operatorscrew 25 in the sleeve 30 moves the support rod 24 inwardly to engagethe rod string 20 end outwardly to disengage the support rod 24 from therod string 20. The support rod 24 slides inwardly and outwardly in alateral cylindrical bore 26 formed in the upper body 11 of the wellhead.

When it is necessary to perform services or remove components, thewellhead 10 can be shut in using other components (not shown). To thensuspend the rod string 20 in the well from the wellhead 10, the rodstring 20 is raised to an elevation at which the coupling flange 33 isabove the intersection of bore 26 in the upper body 11 with the verticalbore 15 through the body. The operator screw 25 is rotated to drive thesupport rod 24 inwardly to the locked position shown in FIG. 2 at whichthe inward ends of the opposite sides of the rod 24 engage the inwardend of the blind bore 26 so that the open inward end of the rod 24 isaround the rod string 20 below the coupling flange 33. At this fullylocked position of the support rod 24, the rod string 20 below theflange 33 is within slot 32 with the lower cylindrical surface portion32 a of the slot engaging the rod string 20 below the flange 33 limitingthe inward movement of the support rod 24. The rod string 20 is thenlowered with the flange 33 entering the upper slot portion 32 b of therod 24. The lower edge of the flange 33 engages the support shoulder 32e of the support rod 24 at the lower end of the upper slot portion 32 bso that the lower end of the flange 33 rests on the support shoulder 32e thereby suspending the rod string 20 in the well. With the rod string20 locked at a suspended position in the wellhead 10, various procedurescan be performed, such as closing blowout preventer ram assemblies (notshown) and the like.

As can be seen, the lock assembly 23 discussed above uses a support rod24 with a shoulder 32 e to engage under a flange 33 on the rod string20. In many reciprocating installations, this form of engagement as wellas others used in the prior art may damage the sealing surface of thepolished rod section, which will eventually damage the seals in astuffing box or elsewhere on a wellhead.

The subject matter of the present disclosure is directed to overcoming,or at least reducing the effects of, one or more of the problems setforth above.

SUMMARY OF THE DISCLOSURE

According to the present disclosure, an apparatus is used with awellhead having a downhole unit operated with a rod string extendingdownhole from an uphole unit at the wellhead. The apparatus comprises arod segment and opposing catchers. The rod segment couples to the rodstring and has first opposing surfaces facing in first opposingdirections. The rod segment is movable in the wellhead. For areciprocating system, the rod segment can be moved longitudinally in thewellhead as the uphole unit reciprocates the rod string to operate thedownhole unit. For a rotary system, the rod segment can be rotatable inthe wellhead as the uphole unit rotates the rod string to operate thedownhole unit.

The opposing catchers are movably laterally in the wellhead relative tothe rod segment. Each of the catchers has a face with second opposingsurfaces facing in second opposing directions opposite to the firstopposing directions. The catchers moved in a first condition in thewellhead have the second opposing surfaces of the faces disengaged fromthe first opposing surfaces of the rod segment. Alternatively, thecatchers moved in a second condition in the wellhead have the secondopposing surfaces of the face engaged with the first opposing surfacesof the rod segment.

In use, the second opposing surfaces of the face engaged with the firstopposing surfaces of the rod segment restrain movement of the rodsegment longitudinally in opposing directions. Likewise, the oppositecatches in the engaged condition restrain movement of the rod segmentlaterally.

In one embodiment, the first opposing surfaces can comprise surfacesfacing inward toward one another forming a plurality of troughs definedcircumferentially about the rod segment. As a corollary, the secondopposing surfaces can then comprise surfaces facing outward away fromone another forming a plurality of teeth projecting from the face formating in the troughs of the rod segment.

In another embodiment, the first opposing surfaces can comprise outerportions of a concavity defined circumferentially about the rod segment.To be complimentary, the second opposing surfaces can then compriseouter portions of a convexity extending from the face and positionableadjacent the concavity of the rod segment.

The rod segment can be separately coupleable to sections of a rodstring. For example, a first end of the rod segment can be coupleable toa first section of the rod string, while a second end of the rod segmentis coupleable to a second section of the rod string.

The apparatus can further comprise an actuator coupling to one of thecatchers and operable to move the catcher between the engaged anddisengaged conditions. For example, the actuator can comprise an armcoupling to the catcher and movable laterally relative to the rodsegment. In turn, the catcher may define a slot, and the arm cancomprise a key coupling with the slot.

According to the present disclosure, an apparatus is used with awellhead having a downhole unit operated with a rod string extendingdownhole from an uphole unit at the wellhead. The apparatus comprises acomponent, a rod segment, and opposing catchers. The component isdisposed on the wellhead. The component has an axial bore for passage ofthe rod string and has first cross-openings communicating with the axialbore. As before, the rod segment couples to the rod string and has firstopposing surfaces facing inward toward one another.

Again, the rod segment is movable in the axial bore of the component.For a reciprocating system, for example, the rod segment can be movedlongitudinally in the component as the uphole unit reciprocates the rodstring to operate the downhole unit. For a rotary system, the rodsegment can be rotatable in the component as the uphole unit rotates therod string to operate the downhole unit.

The opposing catchers are movable laterally in the first cross-openingsof the component relative to the rod segment. As before, each of thecatchers has a face with second opposing surface facing outward from oneanother. The catchers moved in a first condition in the component havethe second opposing surfaces disengaged from the first opposing surfacesof the rod segment. Alternatively, the catchers moved in a secondcondition in the component have the second opposing surfaces engagedwith the first opposing surfaces of the rod segment.

The rod segment can comprise a polished section. The component can havesecond cross-openings communicating with the axial bore. In thisinstance, the apparatus can comprise rams movably laterally in thesecond cross-openings relative to the rod segment. The rams movablebetween engaged and disengaged conditions with the polished section ofthe rod segment. For its part, the component can comprise at least oneflange disposed at one end thereof that is coupleable with a portion ofthe wellhead.

According to the present disclosure, an apparatus is used with awellhead having a downhole unit operated with a rod string extendingdownhole from an uphole unit at the wellhead. The apparatus comprises arod segment and opposing catchers. The rod segment couples to the rodstring and has a first, downward-facing profile. The rod segment ismovable axially in the wellhead.

The opposing catchers are movable laterally in the wellhead relative tothe rod segment. A first of the catchers has a first forked support witha second, upward facing profile. The catchers moved in a first conditionin the component has the second profile disengaged from the firstprofile of the rod segment. Alternatively, the catchers moved in asecond condition in the component have the second profile engaged withthe first profile of the rod segment.

A second of the opposing catchers can comprise a second forked supportfitting under at least a portion of the first forked support when in thesecond condition. Alternatively, the rod segment can comprise a third,upward-facing profile. A second of the opposing catchers can comprise asecond forked support with a fourth, downward facing profile forengagement with the third profile.

According to the present disclosure, an artificial lift system for awell comprises an uphole pump unit, a downhole pump unit, and anapparatus. The uphole pump unit at the well is operable to reciprocate arod string in the well, and the downhole pump unit in the well isoperable to lift fluid in the well in response to the reciprocation ofthe rod string. The apparatus can be similar to that disclosed above andcan be disposed between the uphole and downhole pump units.

According to the present disclosure, methods are used with a wellheadhaving a downhole unit operated with a rod string extending downholefrom an uphole unit at the wellhead. The methods include steps forengaging a rod segment with opposing catchers and retaining movement ofthe rod segment in the wellhead.

The foregoing summary is not intended to summarize each potentialembodiment or every aspect of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a reciprocating rod lift system as background to thepresent disclosure.

FIG. 2 illustrates a portion of a wellhead having a lock assemblyaccording to the prior art for supporting a rod string.

FIGS. 3A-3B illustrate a top view and a side cross-sectional view of asupport rod for the lock assembly in FIG. 2.

FIGS. 4A-4B illustrate cross-sectional views of a wellhead component,revealing a first rod suspension system according to the presentdisclosure in disengaged and engaged conditions.

FIG. 5 illustrates a detailed view of the catchers and the rod segmentof the first rod suspension system.

FIGS. 6A-6B illustrate cross-sectional views of a wellhead component,revealing a second rod suspension system according to the presentdisclosure in disengaged and engaged conditions.

FIGS. 7A-7B illustrate side and end views of the rod segment for thesecond rod suspension system of the present disclosure.

FIG. 8 illustrates a side view of the rod segment and the opposing rodcatchers in an engaged condition.

FIGS. 9A-9D illustrate perspective, cross-section, top, and back viewsof the rod catcher for the second rod suspension system.

FIGS. 10A-10B illustrate cross-sectional views of a wellhead component,revealing a third rod suspension system according to the presentdisclosure in disengaged and engaged conditions.

FIGS. 11A-11B illustrate a forked catcher for the third rod suspensionsystem in top and front views.

FIG. 11C illustrates a side view of the wellhead component with across-passage for the forked catcher.

FIGS. 12A-12B illustrate cross-sectional views of a wellhead component,revealing a fourth rod suspension system according to the presentdisclosure in disengaged and engaged conditions.

FIG. 13 schematically illustrates a reciprocating pump system at awellhead having a rod suspension system according to the presentdisclosure.

FIG. 14 schematically illustrates a rotating pump system at a wellheadhaving a rod suspension system according to the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

FIGS. 4A-4B illustrate cross-sectional views of a wellhead component 50,revealing a first rod suspension system 56A according to the presentdisclosure in disengaged and engaged conditions. Although not shown, thewellhead component 50 can be used as part of a wellhead having gatevalves, tubing spools, casing hangers, etc. Additionally, any upholeunit, such as a pump jack, a hydraulic assembly, a rotary drive, or thelike can sit on the wellhead component or elsewhere on the wellhead.Additionally, any downhole unit (not shown), such as a reciprocatingplunger pump, a progressive cavity pump, or other downhole pump, can bedisposed downhole in a borehole from the wellhead component 50. Theuphole unit can operate the downhole unit using a rod string RSextending downhole from the wellhead, similar to a reciprocating rodlift system known in the art and described previously or similar to arotary pump system known in the art.

The wellhead component 50 has an axial throughbore 52 for passage of therod string RS, fluid, etc. First cross-openings 54 a communicate withthe bore 52 toward the uphole flange 51 a of the component 50, andsecond cross-openings 54 b can also be provided and can communicate withthe bore 52 toward the downhole flange Sib of the component 50.

The rod suspension system 56A includes a rod segment 60 and opposingcatchers 70. The rod segment 60 couples to the rod string RS and canmove longitudinally in the bore 52 of the wellhead component 50. Forexample, the rod segment 60 can be a pony rod placed at the top end ofthe rod string RS and beneath a polished rod of a surface pumping unit.The rod segment 60 includes a profiled section 62 a and can have apolished section 62 b. The rod segment 60 has a set length to insure theplacement of the profile section 62 a is always in close proximity tothe rod catchers 70.

The first cross-openings 54 a hold the opposing catchers 70, while thesecond cross-openings 54 b can hold sealing rams 90. The catchers 70 canmove laterally in the first cross-openings 54 a of the component 50relative to the rod segment 60. For example, a ram-type system havingactuators (not shown) can be operated to engage the catchers 70 with therod segment 60. The rams 90 can also move laterally in the secondcross-openings 54 b of the component 50 relative to the rod segment 60using a ram-type system having actuators (not shown).

As shown in FIG. 4A, the catchers 70 moved in a first condition (awayfrom one another) in the wellhead component 50 are disengaged from therod segment 60. As shown in FIG. 4B, however, the catchers 70 moved in asecond condition (toward one another) in the wellhead component 50 canengage the rod segment 60 at the profiled section 62 a. When the weightof the rod string RS is slacked, the catchers 70 will then support allof the weight to suspend the rod string RS connected to the segment 60so maintenance and other operations can be performed.

As shown in FIG. 4A, the catchers 70 are moved away from one another inthe disengaged condition, which allows the rod segment 60 to passlongitudinally through the bore 52 of the wellhead component 50, such aswhen reciprocating during operation. As then shown in FIG. 4B, thecatchers 70 can be moved toward one another to engage their faces 72against the profiled section 62 b of the rod segment 60 to hold the rodstring at the wellhead component 50 for maintenance or the like.

At least one or both catcher 70 can be moved by an actuator 80 a (onlyone shown) that couples to the catcher 70 and is operable to move thecatcher 70 between the engaged and disengaged conditions. The actuator80 a has an arm 82 coupling to the catcher 70 and movable laterallyrelative to the rod segment 60. In particular, a key 83 on the arm 82can engage in a slot 73 in the back of the catcher 70. The arm can bemoved in any conventional manner, such as screwing in or out.

In addition to the first cross-openings 54 a for the catchers 70, thewellhead component 50 can have the second cross-openings 54 bcommunicating with the bore 50. Rams 90 can be movable laterally inthese second cross-openings 54 b of the component 50 relative to the rodsegment 60. As shown in FIG. 4B, the rams 90 can be positioned below thecatchers 70 and moved to engage their sealing faces 92 against thepolished section 62 b of the rod segment 60. In this way, the sealingrams 90 can be closed around the polished section 62 b of the segment 60to seal off fluid communication in the axial bore 52 and to insure thewell pressure is isolated so the surface pumping unit can then be safelyremoved.

Another set of sealing rams 90 can be used either in another set ofcross-openings in the same component 50 or used in another component ofthe wellhead. For example, the other set of rams 90 can be a set ofsealing rams positioned above the catcher 70 to seal around an uppersection of the rod segment 60 or around a polished rod of the rod stringRS above the segment 60. Alternatively, the other set of rams 90 can bea set of blind rams positioned in a lowermost position away from thecatchers 70, which can be in the upper-most position in the sequencerams. These and other configurations are possible and may have variousbenefits for operations.

The rams 90 can have faces 92 of known design, such as having anarrangement of rubber and steel for sealing. Overall during use, thesealing rams 90 can seal around a portion of the rod string RS in thebore 52, can seal around the polished section 62 b of the segment 60when supported by the catchers 70, or can close off against one anotherfor shutting the bore 52 in the absence of a rod string.

Further details of the rod suspension system 56A are shown in FIG. 5,which illustrates a detailed view of the rod segment 60 and the opposingcatches 70. The rod segment 60 has a first end 61 a coupleable to afirst section of the rod string (not shown). Similarly, the rod segment60 has a second end 61 b coupleable to a second section of the rodstring. As shown, the first and second ends 61 a-b can be box endshaving internal threads to connect to ends of the rod string directly orwith connectors, as the case may be. In other alternatives, one or bothof the ends 61 a-b can be pin ends having external threads. Between theends 61 a-b, the rod segment 60 has the first, profiled section 62 a andthe second, polished section 62 b.

The faces 72 of the catchers 70 have outward opposing surfaces 74 a-b ofone or more teeth 75. Complementary to this, the profiled section 62 aof the rod segment 60 has inward opposing surfaces 64 a-b of one or moretroughs 65. In the current embodiment, the first opposing surfaces 64a-b on the rod segment 60 form a plurality of the troughs 65 definedcircumferentially about the rod segment 60, and the second opposingsurfaces 74 a-b on the catchers 70 form a plurality of the teeth 75projecting from the face 72.

As can be seen, the teeth 75 are configured to mate in the troughs 65 ofthe rod segment 60. In particular, the catchers 70 moved toward oneanother around the profiled section 62 a of the rod segment 60 engagetheir outward opposing surfaces 74 a-b against the inward opposingsurfaces 64 a-b of the rod segment 60. This retrains movement of the rodsegment 60 axially in opposing directions when supported by the catchers70 in the component's bore 52, as discussed previously. In other words,the engagement of the catches 70 prevent the rod segment 60 from movingaxially up or down in the bore 52. Moreover, the opposing catches 70also retain the rod segment 60 laterally.

In the above embodiment, the first and second opposing surfaces 64 a-b,74 a-b include mating troughs 65 and teeth 75 for axially restrainingthe rod segment 60. Other opposing surfaces can be used. For example,rather than having multiple sets of opposing surfaces 64 a-b along theprofiled section 62 a, the rod segment 60 can have one set of outwardlyopposing surfaces 64 a-b (i.e., in the form of one trough 65). Bycomplement, the faces 72 of the catchers 70 can have one set of inwardopposing surfaces 74 a-b (i.e., in the form of one tooth 75). Thesesurfaces 64 a-b, 74 a-b can be rectilinear (i.e., square, trapezoidal,etc.) as shown or can have other shapes.

Another embodiment of a rod suspension system 56B shown with referenceto FIGS. 6A to 8 has monolithic faces with opposing surfaces for the rodsegment 60 and the catchers 70. More particularly, FIGS. 6A-6Billustrates cross-sectional views of a wellhead component 50, revealingthe second rod suspension system 56B according to the present disclosurein disengaged and engaged conditions. Similar reference numbers are usedfor like components to other embodiments disclosed herein.

The rod segment 60 has a profiled section 62 a with a monolithic face,and the opposing catchers 70 are similarly configured with opposingsurfaces having complementary monolithic faces 72. In particular, FIGS.7A-7B illustrate side and end views of the rod segment 60 for thissecond rod suspension system of the present disclosure. Again, the rodsegment 60 has ends 61 a-b coupleable to sections of the rod string (notshown). The profiled section 62 a of the rod segment 60 has inwardlyopposing surfaces 67 a-b facing toward one another. The surfaces 67 a-bare defined by the outer portions of a concavity 66 formedcircumferentially about the rod segment 60.

By contrast, FIGS. 9A-9D illustrate perspective, cross-section, top, andback views of a rod catcher 70 for the second rod suspension system.Complimentary to the surfaces 67 a-b of the rod segment 60, the face 72of the catcher 70 has a convexity 76 extending therefrom andpositionable adjacent the concavity 66 of the rod segment 60 for matingtherewith. At its outer portions, the convexity 76 has outwardlyopposing surfaces 77 a-b facing away from one another.

Engagement of the catchers 70 with the profiled section 62 a of the rodsegment 60 can follow in a similar manner as described previously. Forinstance, FIG. 6A illustrates a side view of the rod segment 60 andopposing rod catchers 70 in a disengaged condition, and FIG. 6B as wellas FIG. 8 illustrate side views of the rod segment 60 and opposing rodcatchers 70 in an engaged condition.

As best shown in the detail of FIG. 8, the faces 72 of the catchers 70have the outward opposing surfaces 77 a-b of the convexity 76.Complementary to this, the profiled section 62 a of the rod segment 60has the inward opposing surfaces 67 a-b of the concavity 66. Thecatchers 70 moved toward one another around the profiled section 62 a ofthe rod segment 60 engage their outward opposing surfaces 77 a-b againstthe inward opposing surfaces 67 a-b of the rod segment 60. This retrainsmovement of the rod segment 60 longitudinally in opposing directions aswell as laterally when supported by the catchers 70 in the component'sbore 52, as discussed previously.

During operation as shown in FIG. 6A, for example, the catchers 70 aremoved away from one another in a disengaged condition, which allows therod segment 60 to pass longitudinally through the axial bore 52 of thewellhead component 50. As then shown in FIG. 6B, the catchers 70 can bemoved toward one another to engage their faces 72 against the profiledsection 62 b of the rod segment 60 to hold the rod segment 60 andcoupled rod string RS at the wellhead component 50.

As before, one or both of catchers 70 can be moved by an actuator 80 a(only one shown) that couples to the catcher 70 and is operable to movethe catcher 70 between the engaged and disengaged conditions. Theactuator 80 a has an arm 82 coupling to the catcher 70 and movablelaterally relative to the rod segment 60. In particular, a key 83 on thearm 82 can engage in a slot 73 in the back of the catcher 70.

In addition to the first cross-openings 54 a for the catchers 70, thewellhead component 50 can have the second cross-openings 54 bcommunicating with the bore 50. Rams 90 can be movable laterally inthese second cross-openings 54 b of the component 50 relative to the rodsegment 60. As shown in FIG. 6B, the rams 90 can be moved to engagetheir sealing faces 92 against the polished section 62 b of the rodsegment 60 to seal off fluid communication in the axial bore 60.

FIGS. 10A-10B illustrate cross-sectional views of a wellhead component50, revealing a third rod suspension system 56C according to the presentdisclosure in disengaged and engaged conditions. Similar components toother embodiments are given like reference numbers and are not describedagain.

In this system 56C, a first catcher 70 a has a forked support 75 a forsupporting a profile 65 a on the rod segment 60, while a second catcher70 b opposing the first catcher 70 a has a forked support or shelf 75 bfor also supporting the profile 65 a on the rod segment 60. Both of thesupports 75 a-b can engage at least a portion of the profile 65 a. Asparticularly shown herein, the second catcher's support 75 b acts as ashelf and fits under the forked support 75 a on the first catcher 70 a.

In this way, with the catchers 70 a-b retracted in the disengagedcondition shown in FIG. 10A, the rod segment 60 can pass through thecomponent's bore 52. When the catchers 70 a-b are extended to theengaged condition shown in FIG. 10B, the forked support 75 a of thefirst catcher 70 a can support the rod segment 60 and attached rodstring RS by engaging the profile 65 a. The forked shelf 75 b of thesecond catcher 70 b can in turn support the first catcher's forkedsupport 75 a. (Similar to other embodiments, the rod segment 60 can havea polished section 65 c for engagement by the rams 90.)

For reference, FIGS. 11A-11B illustrate an embodiment of the firstforked catcher 70 a for the disclosed rod suspension system in top andfront views. The forked support 75 a preferably has an angled surface orshoulder 77 that can match the profile (65 a) of the rod segment (60).For its part, the second forked catcher 70 b can have orthogonalshoulders for its shelf to rest against the underside of the firstcatcher's forked support 75 a.

To align and guide the forked catcher 70 a, tabs or guides 79 can extendfrom the sides. As shown in the side view of the wellhead component 50in FIG. 11C, the cross-opening 54 a for the first forked catcher (70 a)can have side slots 59 in which the tabs or guides (79) fit.

In the previous embodiment, the second forked catcher 70 b fits under(at least partially) and supports the first forked catcher 70 a. As analternative, FIGS. 12A-12B illustrate cross-sectional views of awellhead component 50, revealing a fourth rod suspension system 56Daccording to the present disclosure in disengaged and engagedconditions. Similar components to other embodiments are given likereference numbers and are not described again.

In this system 56D, the first catcher 70 a has the forked support 75 afor engaging a first profile 65 a on the rod segment 60, while thesecond catcher 70 b opposing the first catcher 70 a also has a forkedsupport 75 b for engaging a second, opposite profile 65 b on the rodsegment 60. In this arrangement, the first forked support 75 a isupward-facing to engage the downward-facing first profile 65 a of thesegment 60, and the second forked support 75 b is downward-facing toengage the upward-facing second profile 65 b of the segment 60.

In this way, with the catchers 70 a-b retracted in the disengagedcondition shown in FIG. 12A, the rod segment 60 can pass through thecomponent's bore 52. When the catchers 70 a-b are extended to theengaged condition shown in FIG. 12B, the forked supports 75 a-b of thefirst and second catcher 70 a-b can engage and support the rod segment60 at both of the opposing profiles 65 a-b.

In embodiments of the rod suspension system 56A-D disclosed herein, theengagement of the faces 72, shoulders 77, and the like of the catchers70 with the profiled section 62 a, profiles 65 a-b, and the like of therod segment 60 suspends the rod string RS without damaging the outsidesurface of the rod segment 60 or rod string RS. The inward and outwardopposing surfaces 74 a-b, shoulders 77, forked supports 75 a-b, and thelike of the catchers 70 and the profiled section 62 a and profiles 65a-b engage one another so that the catchers 70 hold the weight of therod string RS as well as any downward load and any upward load that maybe applied to the rod string as a function of the well pressure.

A number of variations can be used for the inward and outward opposingsurfaces. As discussed above in FIGS. 4A-4B and 5, for example, thesurfaces 74 a-b can use angled shoulder, although square shoulders couldbe used. Additionally, the surfaces 74 a-b can use a series of shouldersfacing both directions. In this way, the one or more surfaces on thecatchers 70 can be formed as a pin, tooth, convexity, etc. of a desiredgeometry that engages in a matching hole, trough, concavity, etc. as theone or more surfaces on the rod segment 60. Other arrangements can beused. In fact, the catchers 70 can intertwine with the rod segment 60 inany number of robust structures.

Although previous arrangements disclosed the opposing surfaces of therod segment 60 facing inward toward one another and disclosed theopposing surfaces of the catchers 70 facing outward away from oneanother, an opposite arrangement can be used.

Although sealing rams 90 have been disclosed for use with the rodsegment 60 as noted above, the engagement of the rod segment 60 and thecatchers 70 may not only support the full weight of the rod string, butcan also help seal off any pressure forces. Also as an alternative, anysealing rams can be used on other components of the wellhead to engageanother polished section of the rod string RS so that the wellheadcomponent 50 disclosed herein can be configured without the secondcross-ports 54 b and the rod segment 60 can be configured without thespecific polished section 62 b.

As has been disclosed herein, the wellhead component 50 of the presentdisclosure having the catchers 70 (with or without sealing rams 90) canbe used on a Blowout Preventer (BOP) of a wellhead where multiplesealing rams are used in the BOP. The rod suspension catchers 70 can bepositioned in any sequence in the BOP relative to the other rams.Preferably, the catchers 70 are either in a middle position or an upperposition in the BOP. Although the catchers 70 are preferably not in alowermost position in the BOP, they could be for a given theimplementation.

For example, FIG. 13 schematically illustrates a pumping system 100Athat can use a rod suspension system 56 according to the presentdisclosure. As shown here, the pumping system 100A can be areciprocating type of system having a plunger pump for the downhole unit108 and having a pump jack 106 or the like as a surface drive. Awellhead 120 has a Blowout Preventer (BOP) 110, a stuffing box 130,polished rod 102, and the like along with catchers 70 and rams 90 of awellhead component 50 according to the present disclosure.

As shown here, the catchers 70 are preferably in an uppermost positionin the BOP 110 because this facilitates the optimum placement of the rodsegment 60 during operations. In particular, to suspend the rod string106 during operations, the rod string 106 can be pulled to its uppermostposition by either the pumping unit 104 (if present) at the surface orby a crane (not shown). When this is done, the profile 62 a on the rodsegment 60 will be more readily situated in the correct position betweenthe opposing catchers 70 in the wellhead component 50.

With the catchers 70 in the uppermost position, lower rams 90 a (in adual ram configuration) or a middle ram 90 b (in a triple configuration)may include seals configured to seal around a polished section 62 b ofthe rod segment 60 or around a normal sucker rod of the rod string 106and not necessarily a polished rod 102. In the triple BOP configuration,the lowermost rams 90 b will most likely always be a set of blind rams.In this way, should the rods 102, 106, and/or 60 come apart, the blindrams 90 b can be activated to seal off the well pressure in the BOP 110without the need for a rod member to be positioned across the rams 90 b.

Furthermore, the polished rod sections 102 are optimally placed abovethe rod segment 60 because the stuffing box 130 normally used to sealagainst the polished rod 102 is above all of the rams 90 a-b in the BOP110. This gives the operator the additional flexibility to suspend therod string 106, seal off the well pressure, and then break theconnection to the polished rods 102 above the rod segment 60 to replacethe stuffing box seals or the like.

In one implementation, the rod segment 60 can be about 36-in in lengthand about 1.5-in in diameter. With such a length for the rod segment 60,it is possible for sealing rams 90 a configured to seal around thesegment's polished rod section 62 b with a 1.5-in sealing dimension.However, other configurations are possible.

For instance, the rod segment 60 can be shorter (say 12-in in length). Achangeover thread on the bottom of the segment 60 can be the size of thesucker rod of the rod string 106 used. In this case, the sealing rams(e.g., 90 a in FIG. 13) in the BOP 110 below the catchers 70 can beconfigured to instead seal around a portion of the sucker rod string 106with an appropriate sealing dimension—instead of around the polishedsection 62 b of the rod segment 60. Being able to seal around the suckerrod string 106 can be beneficial when operators are changing polishedrods 102 out. The shorter rod segment 60 can be fitted on the lower endof any length of upper polished rod 102, and a pony rod (not shown) forspacing of the sucker rod string 106 can extend downhole from the lowerend of the rod segment 60. When the shorter rod segment 60 is lifted upand held by the catchers 70, the lower sealing rams 90 a on the BOP 110can be closed on the sucker rod string 106 or the sucker rod pony usedfor spacing.

Because this rod suspension system 56 can include seal rams 90 a, thesurface pumping unit 104 can be safely removed from the well to performwhatever service is required. The structure in the wellhead 120 can bedesigned with various configurations to distribute the loads between akey way, in interlocking shoulders between the catchers 70 and rodsegments, or between a dual catcher system.

The rod suspension system 56 of the present disclosure can be used withother uphole and downhole units for other pumping assemblies, such asrotary pumping assemblies having a progressive cavity pump or the like.For example, FIG. 14 schematically illustrates a rotary pump assembly100B having a rod suspension system 56 according to the presentdisclosure.

This rotary pump assembly 100B is a progressive cavity pumping system.As such, the assembly 100B includes a progressive cavity pump 140 as thedownhole unit and has a rotary drive 150 as the uphole unit, whichimparts rotation to the progressive cavity pump 140 via a rod string106.

Downhole, the progressive cavity pump 140 installs below the wellhead120 at a substantial depth (e.g., about 2000 m) in the wellbore.Typically, the pump 140 has a single helical-shaped rotor 142 that turnsinside a double helical elastomer-lined stator 144. During operation,the stator 144 attached to production tubing string 14 remainsstationary, and surface drive 150 coupled to rotor 142 by drive string106 cause rotor 142 to turn eccentrically in stator 144. As a result, aseries of sealed cavities form between stator 142 and rotor 144 andprogress from the inlet end to the discharge end of pump 140, whichproduces a non-pulsating positive displacement flow.

At the surface, the surface drive 150 has a drive head 152 mounted abovewellhead 120 and has an electric or hydraulic motor 154 coupled to thedrive head 152 by a pulley/belt assembly or gear box 156. The drive head150 typically includes a stuffing box (not shown), a clamp 158, and apolished rod 159. The stuffing box is used to seal the connection ofdrive head 150 to drive shaft 106, and the clamp 158 and polished rod159 are used to transmit the rotation from the drive head 152 to thedrive shaft 106.

To suspend the rod string 106 for maintenance or the like, a wellheadcomponent 50 at the wellhead 120 has catchers 70 (and optionally rams90). A rod segment 60 of the rod suspension system 56 is connected tothe rod string 106 and is disposed in the wellhead component 50. Thecatchers 70 and the rams 90 can be configured respectively to engage theprofiled section 62 a and the polished section 62 b of the rod segment60 as before to suspend the rod string 106.

For such a rotating system, it may be advantageous to be able to reactto torque in the rod string 106 and prevent rotation while gripping therod string 106 to support its weight at the wellhead 120. Accordingly,the assembly 100B can include components and features to hold the rodstring 106 and prevent it from rotating due to torque and the like. Forexample, back spin retarders, brakes, locking mechanisms, and othercomponents know in the art can be used to prevent rotation of the rodstring 106 when the rod string 106 is being supported by the rodsuspension system 56. Many of these types of components are already usedwith rotary drives for rod strings and can be readily incorporated intothe rod suspension system 56 of the present disclosure.

Moreover, should alignment be achievable between an orientation of therod segment 60 and the catchers 70, then longitudinally arranged slotsand profiles between the outside surface of the rod segment 60 and theinside surfaces of the catchers 70 can be used to prevent rotation ofthe rod segment 60 once aligned and engaged by the catchers 70. Althoughboth longitudinal and rotational support could be provided by the samecatcher 70, separate sets of catchers 70 (one set for longitudinalsupport and another set for rotational support) could preferably be usedin the same or separate wellhead component 50.

The foregoing description of preferred and other embodiments is notintended to limit or restrict the scope or applicability of theinventive concepts conceived of by the Applicants. It will beappreciated with the benefit of the present disclosure that featuresdescribed above in accordance with any embodiment or aspect of thedisclosed subject matter can be utilized, either alone or incombination, with any other described feature, in any other embodimentor aspect of the disclosed subject matter.

In exchange for disclosing the inventive concepts contained herein, theApplicants desire all patent rights afforded by the appended claims.Therefore, it is intended that the appended claims include allmodifications and alterations to the full extent that they come withinthe scope of the following claims or the equivalents thereof.

What is claimed is:
 1. An apparatus for use at a wellhead of a wellhaving a downhole unit operated with a rod string extending downholefrom an uphole unit at the wellhead, the apparatus comprising: a rodsegment coupling to the rod string and having first opposing surfacesfacing in first opposing directions, the rod segment movable in relationto the wellhead; and opposing catchers movable laterally at the wellheadrelative to the rod segment, the opposing catchers each having a facewith second opposing surfaces facing in second opposing directionsopposite to the first opposing directions, the opposing catchers movedin a first condition at the wellhead having the second opposing surfacesof the faces disengaged from the first opposing surfaces of the rodsegment, the opposing catchers moved in a second condition at thewellhead having the second opposing surfaces of the faces engaged withthe first opposing surfaces of the rod segment.
 2. The apparatus ofclaim 1, wherein the first opposing surfaces comprise first inwardsurfaces facing inward toward one another and forming a plurality oftroughs defined circumferentially about the rod segment.
 3. Theapparatus of claim 2, wherein the second opposing surfaces comprisesecond outward surfaces facing outward away from one another and forminga plurality of teeth projecting from the face for mating in the troughsof the rod segment.
 4. The apparatus of claim 1, wherein the firstopposing surfaces comprise first outer portions of a concavity definedcircumferentially about the rod segment.
 5. The apparatus of claim 4,wherein the second opposing surfaces comprise second outer portions of aconvexity extending from the face and positionable adjacent theconcavity of the rod segment.
 6. The apparatus of claim 1, wherein therod segment comprises a first end coupleable to a first section of therod string and comprises a second end coupleable to a second section ofthe rod string.
 7. The apparatus of claim 1, further comprising anactuator coupling to at least one of the opposing catchers and operableto move the at least one opposing catcher between the first and secondconditions.
 8. The apparatus of claim 7, wherein the actuator comprisesan arm coupling to the at least one opposing catcher and movablelaterally relative to the rod segment.
 9. The apparatus of claim 8,wherein the at least one opposing catcher defines a slot, and whereinthe arm comprises a key coupling with the slot.
 10. The apparatus ofclaim 1, wherein the second opposing surfaces of the face engaged withthe first opposing surfaces of the rod segment restrain movement of therod segment longitudinally in opposing directions.
 11. The apparatus ofclaim 1, wherein the opposing catchers in the second condition restrainmovement of the rod segment laterally.
 12. The apparatus of claim 1,further comprising a component disposed at the wellhead, the componenthaving a throughbore for passage of the rod segment and having firstcross-openings for the opposing catchers communicating with thethroughbore.
 13. The apparatus of claim 12, wherein the rod segmentcomprises a polished section.
 14. The apparatus of claim 13, wherein thecomponent comprises opposing rams movable laterally in secondcross-openings of the component relative to the rod segment, theopposing rams movable between sealed and unsealed conditions with thepolished section of the rod segment.
 15. The apparatus of claim 12,wherein the component comprises at least one flange disposed at one endthereof and coupleable with a portion of the wellhead.
 16. An artificiallift system for a well having a wellhead, the system comprising: a rodstring; an uphole unit at the wellhead operable to move the rod stringin the well; a downhole unit in the well operable to lift fluid in thewell in response to the movement of the rod string; and a rod segmentcoupled to the rod string at the wellhead and having first opposingsurfaces facing in first opposing directions; and opposing catchersmovable laterally relative to the rod segment at the wellhead, theopposing catchers each having a face with second opposing surfacesfacing in second opposing directions opposite to the first opposingdirections, the opposing catchers moved in a first condition at thewellhead having the second opposing surfaces of the faces disengagedfrom the first opposing surfaces of the rod segment, the opposingcatchers moved in a second condition at the wellhead having the secondopposing surfaces of the faces engaged with the first opposing surfacesof the rod segment.
 17. The system of claim 16, comprising a componentdisposed at the wellhead, the component having a throughbore for passageof the rod segment and having first cross-openings communicating withthe throughbore for the opposing catchers.
 18. The system of claim 17,wherein the rod segment comprises a polished section; and wherein thecomponent comprises rams movable laterally in a second cross-openingsrelative to the rod segment, the rams movable between sealed andunsealed conditions with the polished section of the rod segment. 19.The system of claim 16, wherein the uphole unit at the wellhead isoperable to reciprocate the rod string longitudinally in the well; andwherein the downhole unit in the well is operable to lift fluid in thewell in response to the reciprocation of the rod string.
 20. The systemof claim 19, wherein the downhole unit comprises a reciprocating rodpump disposed in the well; and wherein the uphole unit comprises a pumpjack or a hydraulic jack.
 21. The system of claim 16, wherein the upholeunit at the wellhead is operable to rotate the rod string in the well;and wherein the downhole unit in the well is operable to lift fluid inthe well in response to the rotation of the rod string.
 22. The systemof claim 21, wherein the downhole unit comprises a progressive cavitypump having a stator with a rotor rotatable therein by the rotation ofthe rod string; and wherein the uphole unit comprises a rotary driveimparting the rotation to the rod string.
 23. An apparatus for use at awellhead having a downhole unit operated with a rod string extendingdownhole from an uphole unit at the wellhead, the apparatus comprising:a rod segment coupling to the rod string and having a downward-facingprofile, the rod segment movable longitudinally relative to thewellhead; and opposing catchers movable laterally in the wellheadrelative to the rod segment, the catchers each having a forked supportwith an upward-facing profile, the catchers moved in a first conditionhaving the upward-facing profiles disengaged from the downward-facingprofile of the rod segment, the catchers moved in a second conditionhaving the upward-facing profiles supporting with the downward-facingprofile of the rod segment.
 24. The apparatus of claim 23, wherein theforked support of a first of the opposing catchers when in the secondcondition fits under at least a portion of the forked support of asecond of the opposing catchers.
 25. An apparatus for use at a wellheadhaving a downhole unit operated with a rod string extending downholefrom an uphole unit at the wellhead, the apparatus comprising: a rodsegment coupling to the rod string and having a first downward-facingprofile and first upward-facing profile, the rod segment movablelongitudinally relative to the wellhead; and opposing catchers movablelaterally in the wellhead relative to the rod segment, a first of theopposing catchers having a first forked support with a secondupward-facing profile, a second of the opposing catchers having a secondforked support with a second downward-facing profile, the opposingcatchers moved in a first condition having the second profilesdisengaged from the first profiles of the rod segment, the opposingcatchers moved in a second condition having the second profiles engagedwith the first profiles of the rod segment.